Cdma2000 1xev-dv System In The Cqi Feedback Method And Channel Estimation

With the advancement of technology, the requisition for information is more than ever. Mobile communication is expected to provide higher QoS and data rate in the field of voice, data and image services. This brings great challenges to the performance of mobile communication.Firstly, we will introduce the development of the 3rd generally, telecommunication Then the background and latest development of CQI research will be presented, and the point of it will also be discussed.The main body of this paper concerns on the channel quality indicator (CQI) transmitted on R-CQICH of 1xEV-DV and assisted channel estimation by CQICH . Our work includes two aspects:(1) A new CQI feedback scheme in terms of CDMA2000 lxEV-DV is proposed and compared with the current CQI feedback method. The basic idea is to introduce an intentionally designed phase variation on the overall CDMA signal that the MS has transmitted. The CQI message is conveyed into the phase variation with DPSK modulation. At the receiver side, we trace the phase by pilot channel and recover CQI information by difference detection. Erasure of phase variation will also be performed to reduce the influence of our method at other channel. The method required no dedicate CQI channel so power and code resources are saved. We have validated the scheme simulation results show that the new method outperforms the scheme standardized in the current version of CDMA2000.(2) We proposed that R-CQICH can be used to assist RL channel estimation. The proposed estimator uses R-CQICH assist estimation when R-CQICH exists. We demodulate R-CQICH and we will get CQI information. Then we use CQI information to erase the phase variation of R-CQICH. In the proposed estimator, R-PICH and phase erased R-CQICH are combined. Energy in R-PICH and R-CQICH is fully utilized and estimation accuracy is improved compared with the estimation only by R-PICH.